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Outbreak of rat mite dermatitis in medical students
S L Chung1, S J Hwang, S B Kwon
1Department of Dermatology, Kyungpook National University School of Medicine, Taegu, South Korea.
Background:
The tropical rat mite, Ornithonyssus bacoti (0. bacoti), is an ectoparasite on many rodents, but when the rodent is not available, humans may become the victim of the mite's bite. The bite induces a nonspecific dermatitis; therefore, it is not easy to diagnose rat mite dermatitis unless the parasites are found.
Materials And Methods:
Ten cases of rat mite dermatitis were found in medical students who had studied in the same room of the library. Their nonspecific dermatitis consisted of small papules, and parasites were found in the skin or in the environment. The mites were collected and identified as O. bacoti, female. Histopathologic studies showed moderate perivascular lymphohistiocytic infiltrations intermingled with some eosinophils. The presence of rodents in or around the room was confirmed by the students, but there had been no preceding rodent eradication. Although the rats were not captured in the library, insecticides were sprayed, and no further problem with either mites or dermatitis developed during the follow-up period.
Conclusions:
Rat mite dermatitis can occur in clusters that involve a common source of exposure to the rat mite epidemiologically. Prompt identification of rat mites and the eradication of mites and rodents from the environment can prevent further spreading of the disease.
Insights
Tropical rat mite (Ornithonyssus bacoti) bites can cause dermatitis in humans, often occurring in clusters. Prompt identification and environmental eradication of mites and rodents are crucial for preventing outbreaks.
Area of Science:
- Dermatology
- Parasitology
- Public Health
Background:
- The tropical rat mite, Ornithonyssus bacoti, is an ectoparasite that can bite humans when rodent hosts are unavailable.
- Rat mite dermatitis presents as nonspecific dermatitis, making diagnosis challenging without parasite identification.
Observation:
- A cluster of ten medical students developed dermatitis in a shared library room.
- Parasites identified as Ornithonyssus bacoti were found on affected individuals and in the environment.
- Histopathology revealed moderate perivascular lymphohistiocytic infiltrations with eosinophils.
Findings:
- The cases were linked to a common source of exposure to Ornithonyssus bacoti.
- Rodent presence was confirmed in the vicinity, with no prior eradication efforts.
- Insecticide application led to the resolution of mite infestation and dermatitis.
Implications:
- Rat mite dermatitis can manifest in epidemiological clusters tied to shared exposure environments.
- Early detection of Ornithonyssus bacoti and integrated pest management are essential for controlling outbreaks.
- Environmental control measures, including rodent eradication and insecticide use, are effective in preventing recurrence.